For the purposes of this Chapter, permanent disablement of a person shall be deemed to have resulted from an accident of the nature referred to in sub-section (1) of section 140 if such person has suffered by reason of the accident, any injury or injuries involving:-
(a) permanent privation of the sight of either eye or the hearing of either ear, or privation of any member or joint; or
(b) destruction or permanent impairing of the powers of any member or joint; or
(c) permanent disfiguration of the head or face.